The invention relates to an adhesive application device for applying an adhesive to a material which is moved along a direction of transport x, comprising a nozzle unit having a number of nozzles for applying the adhesive to the material, and to a method for applying adhesive to a material which is moved along a direction of transport x.
Adhesive application devices of this type are used for example in the production of window envelopes. In this case, as a rule first of all a web of paper is guided through a roller system having a number of cutter rollers or similar cutting implements in order to produce an envelope blank. In this case, in a separate cutting process the envelope blank is provided with a cutout for a window. Around this cutout, in a subsequent method step, an adhesive agent is then applied, and a window material is glued on. In this case, as a rule a roller system is also resorted to for applying the adhesive agent. A gumming roller comprising adhesive stamp or a format part for applying the adhesive agent to the envelope blank or to a window film which is adapted to the height and width of the window is rolled onto the envelope blank or the window film, so that the edges of the cutout are provided with sufficient adhesive agent. What is disadvantageous about this method is that a variation in the size of the window, but also a variation in the positioning of the window, always results in the gumming roller being replaced. Thus not only does a separate gumming roller have to be provided and held available for each desired format, they even have to be changed in a costly manner and with production being stopped upon each change of format.
In the case of gluing of paper or cardboard blanks over a large surface area, in addition to the above-mentioned gumming rollers also strips comprising a number of metering nozzles, through which an adhesive agent or an adhesive is applied to the blank, are used. A nozzle system of this type is known for example from the document DE 10 2007 002 980 A1. The metering strip in this case extends over the entire width of the paper web and comprises a number of individual nozzles which are arranged at fixed distances from one another and can be activated individually. Fixed systems of this type are, however, suitable only to a limited extent for use in gluing window elements and, furthermore, are very costly to clean. Owing to the only slight gap between the nozzles and the paper blanks or the roller which transports these paper blanks, cleaning of the nozzles is impeded, which again results in relatively long downtimes of the installation.